Run-on Sentences and Comma Splices

What is a Run-on Sentence and a Comma Splice?

If you join two or more complete sentences without using proper punctuation, then we call it a run-on sentence. Run-on sentences can be long or short, but just because a sentence is long, doesn’t mean that it’s a run-on sentence.
A comma splice is similar to a run-on sentence, but with one difference. In a comma splice, two complete sentences are joined by using a comma improperly.

Why are run-on sentences and comma splices a problem in English?

These types of sentences can often cause misunderstandings, and they generally look and even sound bad to a native speaker.

Why are run-on sentences and comma splices a problem for Spanish speakers?

In English, there are different rules for how to properly construct a sentence. Look at the Spanish sentence below, taken directly from La Nación:

“Asesino es él y asesinos sus más próximos camaradas, porque jefes de una banda narcoterrorista, saboteadora, secuestradora, torturadora y sin otra razón histórica de ser que prolongar su reinado de violencia intimidante, acción atrabiliaria que no va dirigida contra una sangrienta dictadura interna ni contra un agresivo imperialismo externo, sino en contra de un gobierno democráticamente electo y en contra de un indefenso pueblo que la repudia masivamente y desde dentro, como se demostró el año pasado en las calles de las ciudades de medio planeta y en las de Colombia como centro.”

If you translated this sentence directly into English, it would probably make English speakers cry! In schools in the U.S., children are taught the “K.I.S.S. rule” when writing. That means “Keep It Simple, Stupid!” Even though you can correctly form sentences that are very long, it’s not always a great idea. If your writing is unclear or cumbersome, clients will lose interest, and even possibly complain. Run-on sentences and comma splices are notoriously common in English writing by native Spanish speakers.

OK, so how about an example in English?

Look at the following sentence:

“Paul is a very talented chef he still loves to make simple pizzas.”

This is a run-on sentence because both “Paul loves to make pizza” and “he is a very talented chef” can stand on their own as complete sentences. When you have two independent thoughts like this, you cannot combine them into one sentence without separating them somehow.

Now, look at this very similar example:

“Paul is a very talented chef, he still loves to make simple pizzas.”

This is also incorrect, but in this case it’s technically a comma splice.

How can we identify run-on sentences and comma splices?

Look for sentences that have two subjects, or a subject and a pronoun; these types of sentences are often run-on sentences. Comma splices are often easier to spot than run-on sentences because--obviously--comma splices contain a comma...or many commas!

How can we fix run-on sentences and comma splices?

When you encounter a run-on sentence or a comma splice, you will generally need to separate the sentences into two or more parts.
The five techniques listed below can be used to fix both run-on sentences and comma splices. Depending on what you’re trying to express, you’ll have to see which way works best in each situation.
The easiest way to separate a run-on sentence or comma splice is often to just divide the run-on sentence into two sentences:

“Paul is a very talented chef. He still loves to make simple pizzas.”

Alternately, you can add a coordinating conjunction (and, but, or, for, yet, nor, so):

“Paul is a very talented chef, but he still loves to make simple pizzas.”

Another possibility is to add a subordinating conjunction to the sentence (after, although, before, unless, as, because, even though, if, since, until, when, while, etc.):

“Although Paul is a very talented chef, he still loves to make simple pizzas.”

You can also fix the sentence with a semi-colon and a transitional word (however, moreover, on the other hand, nevertheless, instead, also, therefore, consequently, etc.):

“Paul is a very talented chef; however, he still loves to make simple pizzas.”

Finally, you can separate the two sentences with a semi-colon, but that's generally not the preferred method (why not simply separate it into two sentences?):

“Paul is a very talented chef; he still loves to make simple pizzas.”

Depending on the circumstances, one method may work better or seem more natural than another. You may have to change a run-on sentence a few times before it sounds good.

Practice Exercises
Run-on Sentences and Comma Splices

The following sentences all are run-on sentences or contain comma splices. Use one of the techniques mentioned today to correct the sentences.

1. Pablo went to Maxi Bodega, he needed to buy a microwave.

2. Americans shake hands when they meet the Japanese bow.

3. The girls watched TV the boys stayed in the kitchen.

4. I want to learn French Yeison wants to learn German.

5. People in Costa Rica say they like peace they don’t want an army.

6. I will make that change to your account, I just need your telephone number, can you hold on while I pull up some information?

7. Last year we went to Greece, it is a beautiful and exotic country.

8. I have many plans for this coming weekend, if it doesn’t rain we’ll go to La Fortuna, if it does rain we’ll stay at home and play games.

9. I told him that he was wrong, he got angry at me.

10. What’s happening to this neighborhood now you can’t even go outside without being afraid of getting shot!

11. We looked at his car it had a flat, this sort of thing always seems to happen to him.

12. Can you call Kate, her number’s there on the counter.

13. I’d like to present you to Professor Schneider she’s the visiting researcher from Munich.

14. The replacement part will be sent to you in five days, you can expect to receive it by then, if it’s not there call us.

15. Thank you for your interest in our company, it is clients like yourself who make this job rewarding.